The field of this invention is apparatus for bending tubular members such as pipe, thin-walled tubing and the like.
The pipe bending machine of U.S. Pat. No. 3,406,551 was invented by the inventor of the improved pipe bending apparatus disclosed here. The pipe bending machine of U.S. Pat. No. 3,406,551 basically includes a pipe moving mechanism for engaging and moving a piece of pipe longitudinally along a frame; a pair of die members forming a cylindrical passageway to receive and initially bend the pipe and a radial bending arm for engaging and applying a predetermined radius of curvature to the pipe. In actual practice, the machine disclosed in U.S. Pat. No. 3,406,551 has been a very successful machine. The bending cycle such as disclosed in this patent is basically a two-step cycle. During the first step or phase, the pipe moving mechanism feeds the pipe longitudinally through the bending dies and into engagement with the radius setting arm. At the same time, the radius setting arm is pivotally moved from an initial position wherein the straight piece of a pipe is initially engaged to a final, radius-setting position. After the radius setting arm has been moved to the predesignated position for applying the proper radius of curvature, the radius setting arm is held in that position during a second part of the bending cycle wherein the pipe is fed further through the machine by the pipe moving mechanism. Thus, the process of simultaneously moving the radial setting arm to its operative position while feeding the pipe through the bending dies is well known in the art as a result of this patent and perhaps others. Reference is made to U.S. Pat. Nos. 783,716; 913,004; 967,599; 1,515,894; 1,567,107; 1,816,218; 1,943,700; 2,357,006; 2,996,100; 3,116,779; 3,145,756; 3,896,649; and 3,902,344.